Musculoskeletal abilities are crucial for basic physical actions (walking, grasping/moving objects, etc.) and social functioning (job, personal care, etc.). Research that delineates, in a specific manner, links between musculoskeletal, physical, and social function has clinical implications, pointing to rehabilitation of musculoskeletal functions that will have high payoff in older persons' daily lives. this project's goals are to: (1) Develop a protocol and equipment that can be used to assess musculoskeletal function (strength, endurance, range of motion) of older adults in their homes, (2) Develop a physical function test (walking, lifting, bending, manual dexterity, etc.) that covers upper and lower extremity actions, and (3) Study group differentials in musculoskeletal function, relationships of musculoskeletal and physical function, and reliability of strength tests. (1) For musculoskeletal function: (a) Quantitative measurements of isometric strength and endurance at 16 upper and lower extremity sites are obtained using a specially-designed lightweight chair. The chair is made of plastic and aluminum with portable, fold-down features. Strain gauges are mounted directly to the chair for force measurements; electronics for data acquisition are under the chair seat; attached by cable to the chair, a laptop computer contains software that sequences through the protocol and displays force curves. (b) For range of motion, we test 9 movements in standard clinical or goniometric manner. (2) In the physical function test, subjects perform 12-15 actions of everyday life. Levels of physical demand are scaled to provide scores that range from low to moderately high function. Performance is rated, counted, or timed by the interviewer. (3) We obtain data for 220 persons ages 60+ sampled from a human subjects pool maintained by the Division of Geriatrics. Medical history and ACR diagnostic criteria for osteoarthritis (clinical format) are used to classify subjects into Arthritis (osteoarthritis in hand, knee, hip, other location) and Nonarthritis (no rheumatic disease) groups. Persons with rheumatic diseases other than OA are excluded from the study. The data are analyzed for (a) differentials in musculoskeletal function by age, gender, and arthritis status, (b) bivariate associations of musculoskeletal and physical functions, and (c) study of intra- individual reliability of strength tests. Based on this project, the research team will design and propose a large population-based study using the equipment and protocols to yield normative data and more sophisticated scientific results.